Why this sudden change in manik?

Manik has always been a complex character. He never truely cared about someone except fab5. They were like a family. He was in a relationship with Alya. Their relationship lasted for 6 years. Suddenly he met another girl. He was attracted to her innocence. He broke up with Alya due to her lack of trust. His relationship with Nandini grew over the years. In their relationship i never saw a guilty Manik. He was never wondering if he deserved a girl like Nandini. Even when he left her for Dhruv, he knew he was wrong.. but even then he didn't feel he was not good enough for her. Then why does he all of a sudden feel this way? When their relationship came to a point where they both were mature enough to marry each other.. why did he step back? Didn't he feel this way when he said 'ily' to her..? Both Manik and Nandini can't let each other go. One moment they are on a break but an hour later they are hugging each other.. doesn't nandini want a clear answer from manik if he actually wants her in his life or not?

True you said it all. I have same questions. I do understand and accept that they both have matured up. And they won't be all lovely dovely like they used to be in S1. But this is pain stupidity even at age of 15. This is contradicting the mature stuff they are trying to potray.

I don't have any complain to creatives. Just wanted to say that they should both sit and talk like a mature person. Somehow manik's rejection is valid coz hum apne ma baap se hi sab sikhte hai. In upcoming promo we have seen that manik was planning to propose her but something came in between. So for now I stopped my judgment and let the story unfold. Let's see Kya hota hai..